In the art which can be broadly described as separation science, means are provided for isolating, separating, and analyzing mixtures of solutions by selective adsorption on materials such as polymeric materials (e.g. polydivinylbenzene (PDVB) and polymer gel), alumina, silica, and bonded silica. The process is based on differences in the distribution ratios of the components of mixtures between a mutually immiscible mobile and a fixed stationary phase.
Solid phase extraction (SPE) is a laboratory technique for analyzing liquid and mixed liquid/solid samples. The basic objective of such apparatus is to filter the solid portion of the sample and to selectively adsorb compounds from the liquid portion onto a sorbent. The analytes of interest can be subsequently extracted with the solvent and eluted from the sorbent with a minimal amount of an appropriate solvent.
Typical SPE disk apparatus may dispose a sorbent-impregnated SPE disk between an upper funnel and a lower base. A sample may be poured into the funnel, and a vacuum source applied to the base to draw the sample through the disk. The process may be continued until all of the sample to be filtered has passed through the disk.
The analytes bound by the sorbents and trapped in solids filtered out by the disk may be collected by elution. The vacuum may be disconnected and a small amount of extraction solvent applied. The procedure may include a soak period, where analytes bound by the sorbents within the disk desorb and partition into the extraction solvent. After soaking, vacuum may be reapplied, and the solvent collected.